Eyepieces

[Steve Swancott]

I know this about my third post in less than a week but hopefully it's the last...

Will any size and make of eyepiece, a Celestron for example, fit into a telescope? more specifcly my telescope a SW 200?

Thanks

Steve

[Mr Spock]

Eyepieces have the same size fitting, either 1.25" or 2", so make doesn't matter The only thing to check is whether your scope is 1.25" only - some older SWs are.

[Steve Swancott]

1st of all how do i find the fitting? its something i havnt looked for before so i wouldnt know how to tell you! And secondnly is it likely it will be a 1.25 fitting??

Cheers

[Mr Spock]

It will have 1.25" as standard. Some scopes have a tube section you can remove and replace with a 2" fitting - do you have one with the scope?

[Hootsitabernacle]

i think most are 1.25 fitting..the difference between that and the 2" is def noticable tho

[Steve Swancott]

I may do is it a black chunky thing that slots into the eyepiece holder before anything else?

[ronin]

I would guess that the scope will take both 2" and 1.25".

There will be an insert that reduces the diameter from 2" to 1.25"

I would be very surprised if the scope took 0.965" eyepieces, they simply are not catered for these days.

So both diameters unless you lose the reducer insert, in which case buy another one fast. :grin:

[E621Keith]

Unlike most spotting scopes eyepieces that use proprietary connections and not interchangeable between brands, every astronomical eyepiece on the market use either 1.25" or 2" push fit standard. SW200 should be able to take both with the appropriate adapter that is supplied with your scope.

0.965" eyepiece is obsolete and it's unlikely you will come across one even on the second hand market.

[RT65CB-SWL]

Another thing to bear in mind is that some eyepieces are sold as 'parfocal'. ie if your eyepices are from manufacturer "X" then you should not need to refocus everytime you change an eyepiece. If your eyepieces are from "X", "Y" & "Z" then you will need to refocus. Most TeleVue eyepieces are parfocal.

[Pyrodave]

Hi Steve I've attached a couple of photos that might help

My 200P with supplied 1.25" eyepiece

--------------------------------------------------------

same scope with 2" eyepiece and supplied 2" adaptor

[Tinker1947]

Measure the width of the hole the EP goes in,,,,50mm is 2"

[Stargazer_00]

eyepieces can be a bit of a mine field to start with. it's worth having a good run with the supplied eyepieces and if possible going to a local astro club and seeing what other eyepieces offer in terms of characteristics before you start shelling out your hard earned money.

[Aronnax]

If you bought your SW200p new, it should come with two adapters, a 1.25" and a 2". These fit into the focuser, and then you put the EP in to those.

They look like this (1.25" on left, 2" on right):

Just put one in the focusser at a time. DON'T USE BOTH as it will mess up your ability to focus properly:

DON'T DO THIS ^

Hope that helps! Clear skies

p.s: I got these pictures from my SW200p Dob unboxing post here: http://stargazerslou...w/#entry1850126

[Pyrodave]

I did exactly that on my first viewing and wondered why i couldn't focus on anything

[John]

I did exactly that on my first viewing and wondered why i couldn't focus on anything

Lots of folks do that and get rather depressed thinking that either there is something wrong with their scope, their eyepiece or themselves !

The instructions that come with the scope really need to be more helpful on this - the way that Skywatcher handle the 1.25" and 2" adapters is out of line with other brands and not intuitive, in my opinion.

[E621Keith]

I wonder why they didn't just put a regular 2"-1.25" adapter in the 2" visual back like everyone else, instead of having one visual back for 1.25" and another one for 2".

[Stargazer_00]

Lots of folks do that and get rather depressed thinking that either there is something wrong with their scope, their eyepiece or themselves !

The instructions that come with the scope really need to be more helpful on this - the way that Skywatcher handle the 1.25" and 2" adapters is out of line with other brands and not intuitive, in my opinion.

Lots of folks also forget that they were given a 2" adapter at all at the start and when they put their first 2" eyepiece right into the focuser wonder why the damn thing doesn't come to focus.

It's only then you work out that you need an extension for both types of eyepiece.

speaking from experience..

[Tinker1947]

over a bit of time you could end up with quite a few EP Adapters........this is where i am at the moment...

[E621Keith]

over a bit of time you could end up with quite a few EP Adapters........this is where i am at the moment...

We need to start a thread call "Show me a pictures of your adapters"

Nice collection there

[Stargazer_00]

Indeed that made me laugh a bit too. You certainly have your extension needs covered I would hope

[John]

If you stack them all up and add an objective and an eyepiece you would have a nice little refractor there

[Moonshane]

Another thing to bear in mind is that some eyepieces are sold as 'parfocal'. ie if your eyepices are from manufacturer "X" then you should not need to refocus everytime you change an eyepiece. If your eyepieces are from "X", "Y" & "Z" then you will need to refocus. Most TeleVue eyepieces are parfocal.

having parfocal eyepieces is ideal but not necessary really. most Televue eyepieces are not parfocal although some in some ranges are parfocal with others in the range and other ranges. see http://www.televue.com/engine/TV3b_page.asp?id=214&Tab= point F is the reference to consider as this governs parfocality

[Stargazer_00]

I didn't really want to say anything about that parfocaility comment but I agree. That is one of the few things I truly don't give a single care about. I'm sure there is a good reason for it but I truly hope manufacturers aren't making optical compromises to achieve parfocality because it's almost pointless. So long as your focuser/telescope can find focus with the eyepiece then that's just fine. I assume my eyepiece will always need focus when I put it in and some of my eyepieces are near perfect parfocal to each other but I can tell you there is not a bone in my body that will let me put in an eyepiece and not touch the focuser dial. Even if I knew it was absolutely spot on match I'd still give it a little tweak "just to be sure".

It's that irresitable urge to "just be sure" that makes parfocality pointless. If you're going to be sure you might as well do something that contributes!

[rwilkey]

PM sent

[Steve Swancott]

I did exactly that on my first viewing and wondered why i couldn't focus on anything

same